# Is DeepSeek V4.1 Flash free? Open weights, API costs and credit By SeedRouter · Published 2026-09-28 · Updated 2026-09-28 DeepSeek V4.1 Flash is free to download but not free to use through an API. DeepSeek publishes the weights on [Hugging Face](https://huggingface.co/deepseek-ai/DeepSeek-V4.1-Flash), so anyone can get them at no cost. Running a 552-billion-parameter model yourself takes multi-GPU hardware, and DeepSeek's own API bills it per token. It is one of the cheapest models to call, though, and on SeedRouter every new account starts with a small free balance, which covers hundreds of short answers. ## Is DeepSeek V4.1 Flash open source? Its weights are public. DeepSeek links the model and its technical report on Hugging Face from its [release notes](https://api-docs.deepseek.com/news/news260910). Downloading them costs nothing. Read the license published with the weights before using the model commercially. ## Can I run DeepSeek V4.1 Flash locally for free? Only with large hardware. DeepSeek V4.1 Flash is a 552-billion-parameter mixture-of-experts model. It activates only 8B parameters to read input and 16B to write output, which keeps compute per token low, but every weight still has to be loaded. That means a multi-GPU server, not a laptop. For most people, calling it through an API costs far less than the hardware to run it. ## Is the DeepSeek V4.1 Flash API free? No. DeepSeek's [pricing page](https://api-docs.deepseek.com/quick_start/pricing) states that "the expense = number of tokens × price", deducted from your "topped-up balance or granted balance". SeedRouter bills it per token too. It is cheap per token, and cheaper still off-peak: every hour outside 01:00–04:00 and 06:00–10:00 UTC on weekdays, and all weekend, costs half. The live SeedRouter rates: ### DeepSeek V4.1 Flash Current rates are temporarily unavailable. No price estimate is provided; unavailable rates must not be interpreted as free usage. ## How far does the free balance go? At today's peak rates, a short answer with thinking off costs a few hundredths of a cent. In our test, a two-paragraph answer used about 30 input and 260 output tokens. The free balance covers hundreds of answers like that, and twice as many off-peak. Answers with thinking on use more output, so they cost more. ## How do I try DeepSeek V4.1 Flash for next to nothing? 1. Create a SeedRouter account; the free balance is added automatically. 2. Open the [DeepSeek V4.1 Flash playground](https://seedrouter.ai/models/deepseek-v4-1-flash#playground) and send a short prompt with thinking off. 3. Check the tokens and cost under each answer, then decide whether to top up. A request that fails is not charged, so a bad prompt or a wrong parameter costs nothing. ## How do I keep DeepSeek V4.1 Flash cheap after the trial? * **Run flexible work off-peak**, when every rate is half. * **Turn thinking off for simple steps.** Reasoning is output, and output is the dearest line. * **Reuse context at the start of the prompt.** Caching is automatic, and cache hits cost about 2% of fresh input. The [DeepSeek V4.1 Flash pricing guide](https://seedrouter.ai/blog/deepseek-v4-1-flash-api-pricing) has the billing formula and worked examples. ## Frequently asked questions ### Is there a free DeepSeek V4.1 Flash API key? No key is free to use indefinitely. A SeedRouter key comes with a small free balance on a new account; after that you pay per token. ### Is DeepSeek V4.1 Flash free for commercial use? The weights are free to download, and the license published with them sets the terms for commercial use. Calling the model through an API is paid per token either way. ### Do I need a subscription? Not on SeedRouter. You top up a balance and pay per token, with no plan and no monthly fee. ### How do I call it from code? The [DeepSeek V4.1 Flash API guide](https://seedrouter.ai/blog/deepseek-v4-1-flash-api) shows how to get a key and make the first call.